/**
 * Copyright (c) 2006-2015, JGraph Ltd
 * Copyright (c) 2006-2015, Gaudenz Alder
 */
/**
 * Class: mxGraphHandler
 *
 * Graph event handler that handles selection. Individual cells are handled
 * separately using <mxVertexHandler> or one of the edge handlers. These
 * handlers are created using <mxGraph.createHandler> in
 * <mxGraphSelectionModel.cellAdded>.
 *
 * To avoid the container to scroll a moved cell into view, set
 * <scrollAfterMove> to false.
 *
 * Constructor: mxGraphHandler
 *
 * Constructs an event handler that creates handles for the
 * selection cells.
 *
 * Parameters:
 *
 * graph - Reference to the enclosing <mxGraph>.
 */
function mxGraphHandler(graph) {
    this.graph = graph;
    this.graph.addMouseListener(this);

    // Repaints the handler after autoscroll
    this.panHandler = mxUtils.bind(this, function () {
        if (!this.suspended) {
            this.updatePreview();
            this.updateHint();
        }
    });

    this.graph.addListener(mxEvent.PAN, this.panHandler);

    // Handles escape keystrokes
    this.escapeHandler = mxUtils.bind(this, function (sender, evt) {
        this.reset();
    });

    this.graph.addListener(mxEvent.ESCAPE, this.escapeHandler);

    // Updates the preview box for remote changes
    this.refreshHandler = mxUtils.bind(this, function (sender, evt) {
        // Merges multiple pending calls
        if (this.refreshThread) {
            window.clearTimeout(this.refreshThread);
        }

        // Waits for the states and handlers to be updated
        this.refreshThread = window.setTimeout(mxUtils.bind(this, function () {
            this.refreshThread = null;

            if (this.first != null && !this.suspended) {
                // Updates preview with no translate to compute bounding box
                var dx = this.currentDx;
                var dy = this.currentDy;
                this.currentDx = 0;
                this.currentDy = 0;
                this.updatePreview();
                this.bounds = this.graph.getView().getBounds(this.cells);
                this.pBounds = this.getPreviewBounds(this.cells);

                if (this.pBounds == null && !this.livePreviewUsed) {
                    this.reset();
                }
                else {
                    // Restores translate and updates preview
                    this.currentDx = dx;
                    this.currentDy = dy;
                    this.updatePreview();
                    this.updateHint();

                    if (this.livePreviewUsed) {
                        // Forces update to ignore last visible state
                        this.setHandlesVisibleForCells(
                            this.graph.selectionCellsHandler.
                                getHandledSelectionCells(), false, true);
                        this.updatePreview();
                    }
                }
            }
        }), 0);
    });

    this.graph.getModel().addListener(mxEvent.CHANGE, this.refreshHandler);
    this.graph.addListener(mxEvent.REFRESH, this.refreshHandler);

    this.keyHandler = mxUtils.bind(this, function (e) {
        if (this.graph.container != null && this.graph.container.style.visibility != 'hidden' &&
            this.first != null && !this.suspended) {
            var clone = this.graph.isCloneEvent(e) &&
                this.graph.isCellsCloneable() &&
                this.isCloneEnabled();

            if (clone != this.cloning) {
                this.cloning = clone;
                this.checkPreview();
                this.updatePreview();
            }
        }
    });

    mxEvent.addListener(document, 'keydown', this.keyHandler);
    mxEvent.addListener(document, 'keyup', this.keyHandler);
};

/**
 * Variable: graph
 *
 * Reference to the enclosing <mxGraph>.
 */
mxGraphHandler.prototype.graph = null;

/**
 * Variable: maxCells
 *
 * Defines the maximum number of cells to paint subhandles
 * for. Default is 50 for Firefox and 20 for IE. Set this
 * to 0 if you want an unlimited number of handles to be
 * displayed. This is only recommended if the number of
 * cells in the graph is limited to a small number, eg.
 * 500.
 */
mxGraphHandler.prototype.maxCells = (mxClient.IS_IE) ? 20 : 50;

/**
 * Variable: enabled
 *
 * Specifies if events are handled. Default is true.
 */
mxGraphHandler.prototype.enabled = true;

/**
 * Variable: highlightEnabled
 *
 * Specifies if drop targets under the mouse should be enabled. Default is
 * true.
 */
mxGraphHandler.prototype.highlightEnabled = true;

/**
 * Variable: cloneEnabled
 *
 * Specifies if cloning by control-drag is enabled. Default is true.
 */
mxGraphHandler.prototype.cloneEnabled = true;

/**
 * Variable: moveEnabled
 *
 * Specifies if moving is enabled. Default is true.
 */
mxGraphHandler.prototype.moveEnabled = true;

/**
 * Variable: guidesEnabled
 *
 * Specifies if other cells should be used for snapping the right, center or
 * left side of the current selection. Default is false.
 */
mxGraphHandler.prototype.guidesEnabled = false;

/**
 * Variable: handlesVisible
 *
 * Whether the handles of the selection are currently visible.
 */
mxGraphHandler.prototype.handlesVisible = true;

/**
 * Variable: guide
 *
 * Holds the <mxGuide> instance that is used for alignment.
 */
mxGraphHandler.prototype.guide = null;

/**
 * Variable: currentDx
 *
 * Stores the x-coordinate of the current mouse move.
 */
mxGraphHandler.prototype.currentDx = null;

/**
 * Variable: currentDy
 *
 * Stores the y-coordinate of the current mouse move.
 */
mxGraphHandler.prototype.currentDy = null;

/**
 * Variable: updateCursor
 *
 * Specifies if a move cursor should be shown if the mouse is over a movable
 * cell. Default is true.
 */
mxGraphHandler.prototype.updateCursor = true;

/**
 * Variable: selectEnabled
 *
 * Specifies if selecting is enabled. Default is true.
 */
mxGraphHandler.prototype.selectEnabled = true;

/**
 * Variable: removeCellsFromParent
 *
 * Specifies if cells may be moved out of their parents. Default is true.
 */
mxGraphHandler.prototype.removeCellsFromParent = true;

/**
 * Variable: removeEmptyParents
 *
 * If empty parents should be removed from the model after all child cells
 * have been moved out. Default is true.
 */
mxGraphHandler.prototype.removeEmptyParents = false;

/**
 * Variable: connectOnDrop
 *
 * Specifies if drop events are interpreted as new connections if no other
 * drop action is defined. Default is false.
 */
mxGraphHandler.prototype.connectOnDrop = false;

/**
 * Variable: scrollOnMove
 *
 * Specifies if the view should be scrolled so that a moved cell is
 * visible. Default is true.
 */
mxGraphHandler.prototype.scrollOnMove = true;

/**
 * Variable: minimumSize
 *
 * Specifies the minimum number of pixels for the width and height of a
 * selection border. Default is 6.
 */
mxGraphHandler.prototype.minimumSize = 6;

/**
 * Variable: previewColor
 *
 * Specifies the color of the preview shape. Default is black.
 */
mxGraphHandler.prototype.previewColor = 'black';

/**
 * Variable: htmlPreview
 *
 * Specifies if the graph container should be used for preview. If this is used
 * then drop target detection relies entirely on <mxGraph.getCellAt> because
 * the HTML preview does not "let events through". Default is false.
 */
mxGraphHandler.prototype.htmlPreview = false;

/**
 * Variable: shape
 *
 * Reference to the <mxShape> that represents the preview.
 */
mxGraphHandler.prototype.shape = null;

/**
 * Variable: scaleGrid
 *
 * Specifies if the grid should be scaled. Default is false.
 */
mxGraphHandler.prototype.scaleGrid = false;

/**
 * Variable: rotationEnabled
 *
 * Specifies if the bounding box should allow for rotation. Default is true.
 */
mxGraphHandler.prototype.rotationEnabled = true;

/**
 * Variable: maxLivePreview
 *
 * Maximum number of cells for which live preview should be used. Default is 0
 * which means no live preview.
 */
mxGraphHandler.prototype.maxLivePreview = 0;

/**
 * Variable: allowLivePreview
 *
 * If live preview is allowed on this system. Default is true for systems with
 * SVG support.
 */
mxGraphHandler.prototype.allowLivePreview = mxClient.IS_SVG;

/**
 * Function: isEnabled
 *
 * Returns <enabled>.
 */
mxGraphHandler.prototype.isEnabled = function () {
    return this.enabled;
};

/**
 * Function: setEnabled
 *
 * Sets <enabled>.
 */
mxGraphHandler.prototype.setEnabled = function (value) {
    this.enabled = value;
};

/**
 * Function: isCloneEnabled
 *
 * Returns <cloneEnabled>.
 */
mxGraphHandler.prototype.isCloneEnabled = function () {
    return this.cloneEnabled;
};

/**
 * Function: setCloneEnabled
 *
 * Sets <cloneEnabled>.
 *
 * Parameters:
 *
 * value - Boolean that specifies the new clone enabled state.
 */
mxGraphHandler.prototype.setCloneEnabled = function (value) {
    this.cloneEnabled = value;
};

/**
 * Function: isMoveEnabled
 *
 * Returns <moveEnabled>.
 */
mxGraphHandler.prototype.isMoveEnabled = function () {
    return this.moveEnabled;
};

/**
 * Function: setMoveEnabled
 *
 * Sets <moveEnabled>.
 */
mxGraphHandler.prototype.setMoveEnabled = function (value) {
    this.moveEnabled = value;
};

/**
 * Function: isSelectEnabled
 *
 * Returns <selectEnabled>.
 */
mxGraphHandler.prototype.isSelectEnabled = function () {
    return this.selectEnabled;
};

/**
 * Function: setSelectEnabled
 *
 * Sets <selectEnabled>.
 */
mxGraphHandler.prototype.setSelectEnabled = function (value) {
    this.selectEnabled = value;
};

/**
 * Function: isRemoveCellsFromParent
 *
 * Returns <removeCellsFromParent>.
 */
mxGraphHandler.prototype.isRemoveCellsFromParent = function () {
    return this.removeCellsFromParent;
};

/**
 * Function: setRemoveCellsFromParent
 *
 * Sets <removeCellsFromParent>.
 */
mxGraphHandler.prototype.setRemoveCellsFromParent = function (value) {
    this.removeCellsFromParent = value;
};

/**
 * Function: isPropagateSelectionCell
 *
 * Returns true if the given cell and parent should propagate
 * selection state to the parent.
 */
mxGraphHandler.prototype.isPropagateSelectionCell = function (cell, immediate, me) {
    var parent = this.graph.model.getParent(cell);

    if (immediate) {
        var geo = (this.graph.model.isEdge(cell)) ? null :
            this.graph.getCellGeometry(cell);

        return !this.graph.isSiblingSelected(cell) &&
            ((geo != null && geo.relative) ||
                !this.graph.isSwimlane(parent));
    }
    else {
        return (!this.graph.isToggleEvent(me.getEvent()) ||
            (!this.graph.isSiblingSelected(cell) &&
                !this.graph.isCellSelected(cell) &&
                (!this.graph.isSwimlane(parent)) ||
                this.graph.isCellSelected(parent))) &&
            (this.graph.isToggleEvent(me.getEvent()) ||
                !this.graph.isCellSelected(parent));
    }
};

/**
 * Function: getInitialCellForEvent
 *
 * Hook to return initial cell for the given event. This returns
 * the topmost cell that is not a swimlane or is selected.
 */
mxGraphHandler.prototype.getInitialCellForEvent = function (me) {
    var state = me.getState();

    if ((!this.graph.isToggleEvent(me.getEvent()) || !mxEvent.isAltDown(me.getEvent())) &&
        state != null && !this.graph.isCellSelected(state.cell)) {
        var model = this.graph.model;
        var next = this.graph.view.getState(model.getParent(state.cell));

        while (next != null && !this.graph.isCellSelected(next.cell) &&
            (model.isVertex(next.cell) || model.isEdge(next.cell)) &&
            this.isPropagateSelectionCell(state.cell, true, me)) {
            state = next;
            next = this.graph.view.getState(this.graph.getModel().getParent(state.cell));
        }
    }

    return (state != null) ? state.cell : null;
};

/**
 * Function: isDelayedSelection
 *
 * Returns true if the cell or one of its ancestors is selected.
 */
mxGraphHandler.prototype.isDelayedSelection = function (cell, me) {
    if (!this.graph.isToggleEvent(me.getEvent()) || !mxEvent.isAltDown(me.getEvent())) {
        while (cell != null) {
            if (this.graph.selectionCellsHandler.isHandled(cell)) {
                return this.graph.cellEditor.getEditingCell() != cell;
            }

            cell = this.graph.model.getParent(cell);
        }
    }

    return this.graph.isToggleEvent(me.getEvent()) && !mxEvent.isAltDown(me.getEvent());
};

/**
 * Function: selectDelayed
 *
 * Implements the delayed selection for the given mouse event.
 */
mxGraphHandler.prototype.selectDelayed = function (me) {
    if (!this.graph.popupMenuHandler.isPopupTrigger(me)) {
        var cell = me.getCell();

        if (cell == null) {
            cell = this.cell;
        }

        this.selectCellForEvent(cell, me);
    }
};

/**
 * Function: selectCellForEvent
 *
 * Selects the given cell for the given <mxMouseEvent>.
 */
mxGraphHandler.prototype.selectCellForEvent = function (cell, me) {
    var state = this.graph.view.getState(cell);

    if (state != null) {
        if (me.isSource(state.control)) {
            this.graph.selectCellForEvent(cell, me.getEvent());
        }
        else {
            if (!this.graph.isToggleEvent(me.getEvent()) ||
                !mxEvent.isAltDown(me.getEvent())) {
                var model = this.graph.getModel();
                var parent = model.getParent(cell);

                while (this.graph.view.getState(parent) != null &&
                    (model.isVertex(parent) || model.isEdge(parent)) &&
                    this.isPropagateSelectionCell(cell, false, me)) {
                    cell = parent;
                    parent = model.getParent(cell);
                }
            }

            this.graph.selectCellForEvent(cell, me.getEvent());
        }
    }

    return cell;
};

/**
 * Function: consumeMouseEvent
 *
 * Consumes the given mouse event. NOTE: This may be used to enable click
 * events for links in labels on iOS as follows as consuming the initial
 * touchStart disables firing the subsequent click event on the link.
 *
 * <code>
 * mxGraphHandler.prototype.consumeMouseEvent = function(evtName, me)
 * {
 *   var source = mxEvent.getSource(me.getEvent());
 *
 *   if (!mxEvent.isTouchEvent(me.getEvent()) || source.nodeName != 'A')
 *   {
 *     me.consume();
 *   }
 * }
 * </code>
 */
mxGraphHandler.prototype.consumeMouseEvent = function (evtName, me) {
    me.consume();
};

/**
 * Function: mouseDown
 *
 * Handles the event by selecing the given cell and creating a handle for
 * it. By consuming the event all subsequent events of the gesture are
 * redirected to this handler.
 */
mxGraphHandler.prototype.mouseDown = function (sender, me) {
    if (!me.isConsumed() && this.isEnabled() && this.graph.isEnabled() &&
        me.getState() != null && !mxEvent.isMultiTouchEvent(me.getEvent())) {
        var cell = this.getInitialCellForEvent(me);
        this.delayedSelection = this.isDelayedSelection(cell, me);
        this.cell = null;

        if (this.isSelectEnabled() && !this.delayedSelection) {
            this.graph.selectCellForEvent(cell, me.getEvent());
        }

        if (this.isMoveEnabled()) {
            var model = this.graph.model;
            var geo = model.getGeometry(cell);

            if (this.graph.isCellMovable(cell) && ((!model.isEdge(cell) || this.graph.getSelectionCount() > 1 ||
                (geo.points != null && geo.points.length > 0) || model.getTerminal(cell, true) == null ||
                model.getTerminal(cell, false) == null) || this.graph.allowDanglingEdges ||
                (this.graph.isCloneEvent(me.getEvent()) && this.graph.isCellsCloneable()))) {
                this.start(cell, me.getX(), me.getY());
            }
            else if (this.delayedSelection) {
                this.cell = cell;
            }

            this.cellWasClicked = true;
            this.consumeMouseEvent(mxEvent.MOUSE_DOWN, me);
        }
    }
};

/**
 * Function: getGuideStates
 *
 * Creates an array of cell states which should be used as guides.
 */
mxGraphHandler.prototype.getGuideStates = function () {
    var parent = this.graph.getDefaultParent();
    var model = this.graph.getModel();

    var filter = mxUtils.bind(this, function (cell) {
        return this.graph.view.getState(cell) != null &&
            model.isVertex(cell) &&
            model.getGeometry(cell) != null &&
            !model.getGeometry(cell).relative;
    });

    return this.graph.view.getCellStates(model.filterDescendants(filter, parent));
};

/**
 * Function: getCells
 *
 * Returns the cells to be modified by this handler. This implementation
 * returns all selection cells that are movable, or the given initial cell if
 * the given cell is not selected and movable. This handles the case of moving
 * unselectable or unselected cells.
 *
 * Parameters:
 *
 * initialCell - <mxCell> that triggered this handler.
 */
mxGraphHandler.prototype.getCells = function (initialCell) {
    if (!this.delayedSelection && this.graph.isCellMovable(initialCell)) {
        return [initialCell];
    }
    else {
        return this.graph.getMovableCells(this.graph.getSelectionCells());
    }
};

/**
 * Function: getPreviewBounds
 *
 * Returns the <mxRectangle> used as the preview bounds for
 * moving the given cells.
 */
mxGraphHandler.prototype.getPreviewBounds = function (cells) {
    var bounds = this.getBoundingBox(cells);

    if (bounds != null) {
        // Corrects width and height
        bounds.width = Math.max(0, bounds.width - 1);
        bounds.height = Math.max(0, bounds.height - 1);

        if (bounds.width < this.minimumSize) {
            var dx = this.minimumSize - bounds.width;
            bounds.x -= dx / 2;
            bounds.width = this.minimumSize;
        }
        else {
            bounds.x = Math.round(bounds.x);
            bounds.width = Math.ceil(bounds.width);
        }

        var tr = this.graph.view.translate;
        var s = this.graph.view.scale;

        if (bounds.height < this.minimumSize) {
            var dy = this.minimumSize - bounds.height;
            bounds.y -= dy / 2;
            bounds.height = this.minimumSize;
        }
        else {
            bounds.y = Math.round(bounds.y);
            bounds.height = Math.ceil(bounds.height);
        }
    }

    return bounds;
};

/**
 * Function: getBoundingBox
 *
 * Returns the union of the <mxCellStates> for the given array of <mxCells>.
 * For vertices, this method uses the bounding box of the corresponding shape
 * if one exists. The bounding box of the corresponding text label and all
 * controls and overlays are ignored. See also: <mxGraphView.getBounds> and
 * <mxGraph.getBoundingBox>.
 *
 * Parameters:
 *
 * cells - Array of <mxCells> whose bounding box should be returned.
 */
mxGraphHandler.prototype.getBoundingBox = function (cells) {
    var result = null;

    if (cells != null && cells.length > 0) {
        var model = this.graph.getModel();

        for (var i = 0; i < cells.length; i++) {
            if (model.isVertex(cells[i]) || model.isEdge(cells[i])) {
                var state = this.graph.view.getState(cells[i]);

                if (state != null) {
                    var bbox = state;

                    if (model.isVertex(cells[i]) && state.shape != null && state.shape.boundingBox != null) {
                        bbox = state.shape.boundingBox;
                    }

                    if (result == null) {
                        result = mxRectangle.fromRectangle(bbox);
                    }
                    else {
                        result.add(bbox);
                    }
                }
            }
        }
    }

    return result;
};

/**
 * Function: createPreviewShape
 *
 * Creates the shape used to draw the preview for the given bounds.
 */
mxGraphHandler.prototype.createPreviewShape = function (bounds) {
    var shape = new mxRectangleShape(bounds, null, this.previewColor);
    shape.isDashed = true;

    if (this.htmlPreview) {
        shape.dialect = mxConstants.DIALECT_STRICTHTML;
        shape.init(this.graph.container);
    }
    else {
        // Makes sure to use either VML or SVG shapes in order to implement
        // event-transparency on the background area of the rectangle since
        // HTML shapes do not let mouseevents through even when transparent
        shape.dialect = (this.graph.dialect != mxConstants.DIALECT_SVG) ?
            mxConstants.DIALECT_VML : mxConstants.DIALECT_SVG;
        shape.init(this.graph.getView().getOverlayPane());
        shape.pointerEvents = false;

        // Workaround for artifacts on iOS
        if (mxClient.IS_IOS) {
            shape.getSvgScreenOffset = function () {
                return 0;
            };
        }
    }

    return shape;
};

/**
 * Function: start
 *
 * Starts the handling of the mouse gesture.
 */
mxGraphHandler.prototype.start = function (cell, x, y, cells) {
    this.cell = cell;
    this.first = mxUtils.convertPoint(this.graph.container, x, y);
    this.cells = (cells != null) ? cells : this.getCells(this.cell);
    this.bounds = this.graph.getView().getBounds(this.cells);
    this.pBounds = this.getPreviewBounds(this.cells);
    this.allCells = new mxDictionary();
    this.cloning = false;
    this.cellCount = 0;

    for (var i = 0; i < this.cells.length; i++) {
        this.cellCount += this.addStates(this.cells[i], this.allCells);
    }

    if (this.guidesEnabled) {
        this.guide = new mxGuide(this.graph, this.getGuideStates());
        var parent = this.graph.model.getParent(cell);
        var ignore = this.graph.model.getChildCount(parent) < 2;

        // Uses connected states as guides
        var connected = new mxDictionary();
        var opps = this.graph.getOpposites(this.graph.getEdges(this.cell), this.cell);

        for (var i = 0; i < opps.length; i++) {
            var state = this.graph.view.getState(opps[i]);

            if (state != null && !connected.get(state)) {
                connected.put(state, true);
            }
        }

        this.guide.isStateIgnored = mxUtils.bind(this, function (state) {
            var p = this.graph.model.getParent(state.cell);

            return state.cell != null && ((!this.cloning &&
                this.isCellMoving(state.cell)) ||
                (state.cell != (this.target || parent) && !ignore &&
                    !connected.get(state) &&
                    (this.target == null || this.graph.model.getChildCount(
                        this.target) >= 2) && p != (this.target || parent)));
        });
    }
};

/**
 * Function: addStates
 *
 * Adds the states for the given cell recursively to the given dictionary.
 */
mxGraphHandler.prototype.addStates = function (cell, dict) {
    var state = this.graph.view.getState(cell);
    var count = 0;

    if (state != null && dict.get(cell) == null) {
        dict.put(cell, state);
        count++;

        var childCount = this.graph.model.getChildCount(cell);

        for (var i = 0; i < childCount; i++) {
            count += this.addStates(this.graph.model.getChildAt(cell, i), dict);
        }
    }

    return count;
};

/**
 * Function: isCellMoving
 *
 * Returns true if the given cell is currently being moved.
 */
mxGraphHandler.prototype.isCellMoving = function (cell) {
    return this.allCells.get(cell) != null;
};

/**
 * Function: useGuidesForEvent
 *
 * Returns true if the guides should be used for the given <mxMouseEvent>.
 * This implementation returns <mxGuide.isEnabledForEvent>.
 */
mxGraphHandler.prototype.useGuidesForEvent = function (me) {
    return (this.guide != null) ? this.guide.isEnabledForEvent(me.getEvent()) &&
        !this.graph.isConstrainedEvent(me.getEvent()) : true;
};

/**
 * Function: snap
 *
 * Snaps the given vector to the grid and returns the given mxPoint instance.
 */
mxGraphHandler.prototype.snap = function (vector) {
    var scale = (this.scaleGrid) ? this.graph.view.scale : 1;

    vector.x = this.graph.snap(vector.x / scale) * scale;
    vector.y = this.graph.snap(vector.y / scale) * scale;

    return vector;
};

/**
 * Function: getDelta
 *
 * Returns an <mxPoint> that represents the vector for moving the cells
 * for the given <mxMouseEvent>.
 */
mxGraphHandler.prototype.getDelta = function (me) {
    var point = mxUtils.convertPoint(this.graph.container, me.getX(), me.getY());

    return new mxPoint(point.x - this.first.x - this.graph.panDx,
        point.y - this.first.y - this.graph.panDy);
};

/**
 * Function: updateHint
 *
 * Hook for subclassers do show details while the handler is active.
 */
mxGraphHandler.prototype.updateHint = function (me) { };

/**
 * Function: removeHint
 *
 * Hooks for subclassers to hide details when the handler gets inactive.
 */
mxGraphHandler.prototype.removeHint = function () { };

/**
 * Function: roundLength
 *
 * Hook for rounding the unscaled vector. Allows for half steps in the raster so
 * numbers coming in should be rounded if no half steps are allowed (ie for non
 * aligned standard moving where pixel steps should be preferred).
 */
mxGraphHandler.prototype.roundLength = function (length) {
    return Math.round(length * 100) / 100;
};

/**
 * Function: isValidDropTarget
 *
 * Returns true if the given cell is a valid drop target.
 */
mxGraphHandler.prototype.isValidDropTarget = function (target, me) {
    return this.graph.model.getParent(this.cell) != target;
};

/**
 * Function: checkPreview
 *
 * Updates the preview if cloning state has changed.
 */
mxGraphHandler.prototype.checkPreview = function () {
    if (this.livePreviewActive && this.cloning) {
        this.resetLivePreview();
        this.livePreviewActive = false;
    }
    else if (this.maxLivePreview >= this.cellCount && !this.livePreviewActive && this.allowLivePreview) {
        if (!this.cloning || !this.livePreviewActive) {
            this.livePreviewActive = true;
            this.livePreviewUsed = true;
        }
    }
    else if (!this.livePreviewUsed && this.shape == null) {
        this.shape = this.createPreviewShape(this.bounds);
    }
};

/**
 * Function: mouseMove
 *
 * Handles the event by highlighting possible drop targets and updating the
 * preview.
 */
mxGraphHandler.prototype.mouseMove = function (sender, me) {
    var graph = this.graph;

    if (!me.isConsumed() && graph.isMouseDown && this.cell != null &&
        this.first != null && this.bounds != null && !this.suspended) {
        // Stops moving if a multi touch event is received
        if (mxEvent.isMultiTouchEvent(me.getEvent())) {
            this.reset();
            return;
        }

        var delta = this.getDelta(me);
        var tol = graph.tolerance;

        if (this.shape != null || this.livePreviewActive || Math.abs(delta.x) > tol || Math.abs(delta.y) > tol) {
            // Highlight is used for highlighting drop targets
            if (this.highlight == null) {
                this.highlight = new mxCellHighlight(this.graph,
                    mxConstants.DROP_TARGET_COLOR, 3);
            }

            var clone = graph.isCloneEvent(me.getEvent()) && graph.isCellsCloneable() && this.isCloneEnabled();
            var gridEnabled = graph.isGridEnabledEvent(me.getEvent());
            var cell = me.getCell();
            var hideGuide = true;
            var target = null;
            this.cloning = clone;

            if (graph.isDropEnabled() && this.highlightEnabled) {
                // Contains a call to getCellAt to find the cell under the mouse
                target = graph.getDropTarget(this.cells, me.getEvent(), cell, clone);
            }

            var state = graph.getView().getState(target);
            var highlight = false;

            if (state != null && (clone || this.isValidDropTarget(target, me))) {
                if (this.target != target) {
                    this.target = target;
                    this.setHighlightColor(mxConstants.DROP_TARGET_COLOR);
                }

                highlight = true;
            }
            else {
                this.target = null;

                if (this.connectOnDrop && cell != null && this.cells.length == 1 &&
                    graph.getModel().isVertex(cell) && graph.isCellConnectable(cell)) {
                    state = graph.getView().getState(cell);

                    if (state != null) {
                        var error = graph.getEdgeValidationError(null, this.cell, cell);
                        var color = (error == null) ?
                            mxConstants.VALID_COLOR :
                            mxConstants.INVALID_CONNECT_TARGET_COLOR;
                        this.setHighlightColor(color);
                        highlight = true;
                    }
                }
            }

            if (state != null && highlight) {
                this.highlight.highlight(state);
            }
            else {
                this.highlight.hide();
            }

            if (this.guide != null && this.useGuidesForEvent(me)) {
                delta = this.guide.move(this.bounds, delta, gridEnabled, clone);
                hideGuide = false;
            }
            else {
                delta = this.graph.snapDelta(delta, this.bounds, !gridEnabled, false, false);
            }

            if (this.guide != null && hideGuide) {
                this.guide.hide();
            }

            // Constrained movement if shift key is pressed
            if (graph.isConstrainedEvent(me.getEvent())) {
                if (Math.abs(delta.x) > Math.abs(delta.y)) {
                    delta.y = 0;
                }
                else {
                    delta.x = 0;
                }
            }

            this.checkPreview();

            if (this.currentDx != delta.x || this.currentDy != delta.y) {
                this.currentDx = delta.x;
                this.currentDy = delta.y;
                this.updatePreview();
            }
        }

        this.updateHint(me);
        this.consumeMouseEvent(mxEvent.MOUSE_MOVE, me);

        // Cancels the bubbling of events to the container so
        // that the droptarget is not reset due to an mouseMove
        // fired on the container with no associated state.
        mxEvent.consume(me.getEvent());
    }
    else if ((this.isMoveEnabled() || this.isCloneEnabled()) && this.updateCursor && !me.isConsumed() &&
        (me.getState() != null || me.sourceState != null) && !graph.isMouseDown) {
        var cursor = graph.getCursorForMouseEvent(me);

        if (cursor == null && graph.isEnabled() && graph.isCellMovable(me.getCell())) {
            if (graph.getModel().isEdge(me.getCell())) {
                cursor = mxConstants.CURSOR_MOVABLE_EDGE;
            }
            else {
                cursor = mxConstants.CURSOR_MOVABLE_VERTEX;
            }
        }

        // Sets the cursor on the original source state under the mouse
        // instead of the event source state which can be the parent
        if (cursor != null && me.sourceState != null) {
            me.sourceState.setCursor(cursor);
        }
    }
};

/**
 * Function: updatePreview
 *
 * Updates the bounds of the preview shape.
 */
mxGraphHandler.prototype.updatePreview = function (remote) {
    if (this.livePreviewUsed && !remote) {
        if (this.cells != null) {
            this.setHandlesVisibleForCells(
                this.graph.selectionCellsHandler.
                    getHandledSelectionCells(), false);
            this.updateLivePreview(this.currentDx, this.currentDy);
        }
    }
    else {
        this.updatePreviewShape();
    }
};

/**
 * Function: updatePreviewShape
 *
 * Updates the bounds of the preview shape.
 */
mxGraphHandler.prototype.updatePreviewShape = function () {
    if (this.shape != null && this.pBounds != null) {
        this.shape.bounds = new mxRectangle(Math.round(this.pBounds.x + this.currentDx),
            Math.round(this.pBounds.y + this.currentDy), this.pBounds.width, this.pBounds.height);
        this.shape.redraw();
    }
};

/**
 * Function: updateLivePreview
 *
 * Updates the bounds of the preview shape.
 */
mxGraphHandler.prototype.updateLivePreview = function (dx, dy) {
    if (!this.suspended) {
        var states = [];

        if (this.allCells != null) {
            this.allCells.visit(mxUtils.bind(this, function (key, state) {
                var realState = this.graph.view.getState(state.cell);

                // Checks if cell was removed or replaced
                if (realState != state) {
                    state.destroy();

                    if (realState != null) {
                        this.allCells.put(state.cell, realState);
                    }
                    else {
                        this.allCells.remove(state.cell);
                    }

                    state = realState;
                }

                if (state != null) {
                    // Saves current state
                    var tempState = state.clone();
                    states.push([state, tempState]);

                    // Makes transparent for events to detect drop targets
                    if (state.shape != null) {
                        if (state.shape.originalPointerEvents == null) {
                            state.shape.originalPointerEvents = state.shape.pointerEvents;
                        }

                        state.shape.pointerEvents = false;

                        if (state.text != null) {
                            if (state.text.originalPointerEvents == null) {
                                state.text.originalPointerEvents = state.text.pointerEvents;
                            }

                            state.text.pointerEvents = false;
                        }
                    }

                    // Temporarily changes position
                    if (this.graph.model.isVertex(state.cell)) {
                        state.x += dx;
                        state.y += dy;

                        // Draws the live preview
                        if (!this.cloning) {
                            state.view.graph.cellRenderer.redraw(state, true);

                            // Forces redraw of connected edges after all states
                            // have been updated but avoids update of state
                            state.view.invalidate(state.cell);
                            state.invalid = false;

                            // Hides folding icon
                            if (state.control != null && state.control.node != null) {
                                state.control.node.style.visibility = 'hidden';
                            }
                        }
                        // Clone live preview may use text bounds
                        else if (state.text != null) {
                            state.text.updateBoundingBox();

                            // Fixes preview box for edge labels
                            if (state.text.boundingBox != null) {
                                state.text.boundingBox.x += dx;
                                state.text.boundingBox.y += dy;
                            }

                            if (state.text.unrotatedBoundingBox != null) {
                                state.text.unrotatedBoundingBox.x += dx;
                                state.text.unrotatedBoundingBox.y += dy;
                            }
                        }
                    }
                }
            }));
        }

        // Resets the handler if everything was removed
        if (states.length == 0) {
            this.reset();
        }
        else {
            // Redraws connected edges
            var s = this.graph.view.scale;

            for (var i = 0; i < states.length; i++) {
                var state = states[i][0];

                if (this.graph.model.isEdge(state.cell)) {
                    var geometry = this.graph.getCellGeometry(state.cell);
                    var points = [];

                    if (geometry != null && geometry.points != null) {
                        for (var j = 0; j < geometry.points.length; j++) {
                            if (geometry.points[j] != null) {
                                points.push(new mxPoint(
                                    geometry.points[j].x + dx / s,
                                    geometry.points[j].y + dy / s));
                            }
                        }
                    }

                    var source = state.visibleSourceState;
                    var target = state.visibleTargetState;
                    var pts = states[i][1].absolutePoints;

                    if (source == null || !this.isCellMoving(source.cell)) {
                        var pt0 = pts[0];
                        state.setAbsoluteTerminalPoint(new mxPoint(pt0.x + dx, pt0.y + dy), true);
                        source = null;
                    }
                    else {
                        state.view.updateFixedTerminalPoint(state, source, true,
                            this.graph.getConnectionConstraint(state, source, true));
                    }

                    if (target == null || !this.isCellMoving(target.cell)) {
                        var ptn = pts[pts.length - 1];
                        state.setAbsoluteTerminalPoint(new mxPoint(ptn.x + dx, ptn.y + dy), false);
                        target = null;
                    }
                    else {
                        state.view.updateFixedTerminalPoint(state, target, false,
                            this.graph.getConnectionConstraint(state, target, false));
                    }

                    state.view.updatePoints(state, points, source, target);
                    state.view.updateFloatingTerminalPoints(state, source, target);
                    state.view.updateEdgeLabelOffset(state);
                    state.invalid = false;

                    // Draws the live preview but avoids update of state
                    if (!this.cloning) {
                        state.view.graph.cellRenderer.redraw(state, true);
                    }
                }
            }

            this.graph.view.validate();
            this.redrawHandles(states);
            this.resetPreviewStates(states);
        }
    }
};

/**
 * Function: redrawHandles
 *
 * Redraws the preview shape for the given states array.
 */
mxGraphHandler.prototype.redrawHandles = function (states) {
    for (var i = 0; i < states.length; i++) {
        var handler = this.graph.selectionCellsHandler.getHandler(states[i][0].cell);

        if (handler != null) {
            handler.redraw(true);
        }
    }
};

/**
 * Function: resetPreviewStates
 *
 * Resets the given preview states array.
 */
mxGraphHandler.prototype.resetPreviewStates = function (states) {
    for (var i = 0; i < states.length; i++) {
        states[i][0].setState(states[i][1]);
    }
};

/**
 * Function: suspend
 *
 * Suspends the livew preview.
 */
mxGraphHandler.prototype.suspend = function () {
    if (!this.suspended) {
        if (this.livePreviewUsed) {
            this.updateLivePreview(0, 0);
        }

        if (this.shape != null) {
            this.shape.node.style.visibility = 'hidden';
        }

        if (this.guide != null) {
            this.guide.setVisible(false);
        }

        this.suspended = true;
    }
};

/**
 * Function: resume
 *
 * Suspends the livew preview.
 */
mxGraphHandler.prototype.resume = function () {
    if (this.suspended) {
        this.suspended = null;

        if (this.livePreviewUsed) {
            this.livePreviewActive = true;
        }

        if (this.shape != null) {
            this.shape.node.style.visibility = 'visible';
        }

        if (this.guide != null) {
            this.guide.setVisible(true);
        }
    }
};

/**
 * Function: resetLivePreview
 *
 * Resets the livew preview.
 */
mxGraphHandler.prototype.resetLivePreview = function () {
    if (this.allCells != null) {
        this.allCells.visit(mxUtils.bind(this, function (key, state) {
            // Restores event handling
            if (state.shape != null && state.shape.originalPointerEvents != null) {
                state.shape.pointerEvents = state.shape.originalPointerEvents;
                state.shape.originalPointerEvents = null;

                // Forces repaint even if not moved to update pointer events
                state.shape.bounds = null;

                if (state.text != null) {
                    state.text.pointerEvents = state.text.originalPointerEvents;
                    state.text.originalPointerEvents = null;
                }
            }

            // Shows folding icon
            if (state.control != null && state.control.node != null &&
                state.control.node.style.visibility == 'hidden') {
                state.control.node.style.visibility = '';
            }

            // Fixes preview box for edge labels
            if (!this.cloning) {
                if (state.text != null) {
                    state.text.updateBoundingBox();
                }
            }

            // Forces repaint of connected edges
            state.view.invalidate(state.cell);
        }));

        // Repaints all invalid states
        this.graph.view.validate();
    }
};

/**
 * Function: setHandlesVisibleForCells
 *
 * Sets wether the handles attached to the given cells are visible.
 *
 * Parameters:
 *
 * cells - Array of <mxCells>.
 * visible - Boolean that specifies if the handles should be visible.
 * force - Forces an update of the handler regardless of the last used value.
 */
mxGraphHandler.prototype.setHandlesVisibleForCells = function (cells, visible, force) {
    if (force || this.handlesVisible != visible) {
        this.handlesVisible = visible;

        for (var i = 0; i < cells.length; i++) {
            var handler = this.graph.selectionCellsHandler.getHandler(cells[i]);

            if (handler != null) {
                handler.setHandlesVisible(visible);

                if (visible) {
                    handler.redraw();
                }
            }
        }
    }
};

/**
 * Function: setHighlightColor
 *
 * Sets the color of the rectangle used to highlight drop targets.
 *
 * Parameters:
 *
 * color - String that represents the new highlight color.
 */
mxGraphHandler.prototype.setHighlightColor = function (color) {
    if (this.highlight != null) {
        this.highlight.setHighlightColor(color);
    }
};

/**
 * Function: mouseUp
 *
 * Handles the event by applying the changes to the selection cells.
 */
mxGraphHandler.prototype.mouseUp = function (sender, me) {
    if (!me.isConsumed()) {
        if (this.livePreviewUsed) {
            this.resetLivePreview();
        }

        if (this.cell != null && this.first != null && (this.shape != null || this.livePreviewUsed) &&
            this.currentDx != null && this.currentDy != null) {
            var graph = this.graph;
            var cell = me.getCell();

            if (this.connectOnDrop && this.target == null && cell != null && graph.getModel().isVertex(cell) &&
                graph.isCellConnectable(cell) && graph.isEdgeValid(null, this.cell, cell)) {
                graph.connectionHandler.connect(this.cell, cell, me.getEvent());
            }
            else {
                var clone = graph.isCloneEvent(me.getEvent()) && graph.isCellsCloneable() && this.isCloneEnabled();
                var scale = graph.getView().scale;
                var dx = this.roundLength(this.currentDx / scale);
                var dy = this.roundLength(this.currentDy / scale);
                var target = this.target;

                if (graph.isSplitEnabled() && graph.isSplitTarget(target, this.cells, me.getEvent())) {
                    graph.splitEdge(target, this.cells, null, dx, dy,
                        me.getGraphX(), me.getGraphY());
                }
                else {
                    this.moveCells(this.cells, dx, dy, clone, this.target, me.getEvent());
                }
            }
        }
        else if (this.isSelectEnabled() && this.delayedSelection && this.cell != null) {
            this.selectDelayed(me);
        }
    }

    // Consumes the event if a cell was initially clicked
    if (this.cellWasClicked) {
        this.consumeMouseEvent(mxEvent.MOUSE_UP, me);
    }

    this.reset();
};

/**
 * Function: reset
 *
 * Resets the state of this handler.
 */
mxGraphHandler.prototype.reset = function () {
    if (this.livePreviewUsed) {
        this.resetLivePreview();
        this.setHandlesVisibleForCells(
            this.graph.selectionCellsHandler.
                getHandledSelectionCells(), true);
    }

    this.destroyShapes();
    this.removeHint();

    this.delayedSelection = false;
    this.livePreviewActive = null;
    this.livePreviewUsed = null;
    this.cellWasClicked = false;
    this.suspended = null;
    this.currentDx = null;
    this.currentDy = null;
    this.cellCount = null;
    this.cloning = false;
    this.allCells = null;
    this.pBounds = null;
    this.guides = null;
    this.target = null;
    this.first = null;
    this.cells = null;
    this.cell = null;
};

/**
 * Function: shouldRemoveCellsFromParent
 *
 * Returns true if the given cells should be removed from the parent for the specified
 * mousereleased event.
 */
mxGraphHandler.prototype.shouldRemoveCellsFromParent = function (parent, cells, evt) {
    if (this.graph.getModel().isVertex(parent)) {
        var pState = this.graph.getView().getState(parent);

        if (pState != null) {
            var pt = mxUtils.convertPoint(this.graph.container,
                mxEvent.getClientX(evt), mxEvent.getClientY(evt));
            var alpha = mxUtils.toRadians(mxUtils.getValue(pState.style, mxConstants.STYLE_ROTATION) || 0);

            if (alpha != 0) {
                var cos = Math.cos(-alpha);
                var sin = Math.sin(-alpha);
                var cx = new mxPoint(pState.getCenterX(), pState.getCenterY());
                pt = mxUtils.getRotatedPoint(pt, cos, sin, cx);
            }

            return !mxUtils.contains(pState, pt.x, pt.y);
        }
    }

    return false;
};

/**
 * Function: moveCells
 *
 * Moves the given cells by the specified amount.
 */
mxGraphHandler.prototype.moveCells = function (cells, dx, dy, clone, target, evt) {
    if (clone) {
        cells = this.graph.getCloneableCells(cells);
    }

    // Removes cells from parent
    var parent = this.graph.getModel().getParent(this.cell);

    if (target == null && this.isRemoveCellsFromParent() &&
        this.shouldRemoveCellsFromParent(parent, cells, evt)) {
        target = this.graph.getDefaultParent();
    }

    // Cloning into locked cells is not allowed
    clone = clone && !this.graph.isCellLocked(target || this.graph.getDefaultParent());

    this.graph.getModel().beginUpdate();
    try {
        var parents = [];

        // Removes parent if all child cells are removed
        if (!clone && target != null && this.removeEmptyParents) {
            // Collects all non-selected parents
            var dict = new mxDictionary();

            for (var i = 0; i < cells.length; i++) {
                dict.put(cells[i], true);
            }

            // LATER: Recurse up the cell hierarchy
            for (var i = 0; i < cells.length; i++) {
                var par = this.graph.model.getParent(cells[i]);

                if (par != null && !dict.get(par)) {
                    dict.put(par, true);
                    parents.push(par);
                }
            }
        }

        // Passes all selected cells in order to correctly clone or move into
        // the target cell. The method checks for each cell if its movable.
        cells = this.graph.moveCells(cells, dx, dy, clone, target, evt);

        // Removes parent if all child cells are removed
        var temp = [];

        for (var i = 0; i < parents.length; i++) {
            if (this.shouldRemoveParent(parents[i])) {
                temp.push(parents[i]);
            }
        }

        this.graph.removeCells(temp, false);
    }
    finally {
        this.graph.getModel().endUpdate();
    }

    // Selects the new cells if cells have been cloned
    if (clone) {
        this.graph.setSelectionCells(cells);
    }

    if (this.isSelectEnabled() && this.scrollOnMove) {
        this.graph.scrollCellToVisible(cells[0]);
    }
};

/**
 * Function: shouldRemoveParent
 *
 * Returns true if the given parent should be removed after removal of child cells.
 */
mxGraphHandler.prototype.shouldRemoveParent = function (parent) {
    var state = this.graph.view.getState(parent);

    return state != null && (this.graph.model.isEdge(state.cell) || this.graph.model.isVertex(state.cell)) &&
        this.graph.isCellDeletable(state.cell) && this.graph.model.getChildCount(state.cell) == 0 &&
        this.graph.isTransparentState(state);
};

/**
 * Function: destroyShapes
 *
 * Destroy the preview and highlight shapes.
 */
mxGraphHandler.prototype.destroyShapes = function () {
    // Destroys the preview dashed rectangle
    if (this.shape != null) {
        this.shape.destroy();
        this.shape = null;
    }

    if (this.guide != null) {
        this.guide.destroy();
        this.guide = null;
    }

    // Destroys the drop target highlight
    if (this.highlight != null) {
        this.highlight.destroy();
        this.highlight = null;
    }
};

/**
 * Function: destroy
 *
 * Destroys the handler and all its resources and DOM nodes.
 */
mxGraphHandler.prototype.destroy = function () {
    this.graph.removeMouseListener(this);
    this.graph.removeListener(this.panHandler);

    if (this.escapeHandler != null) {
        this.graph.removeListener(this.escapeHandler);
        this.escapeHandler = null;
    }

    if (this.refreshHandler != null) {
        this.graph.getModel().removeListener(this.refreshHandler);
        this.graph.removeListener(this.refreshHandler);
        this.refreshHandler = null;
    }

    mxEvent.removeListener(document, 'keydown', this.keyHandler);
    mxEvent.removeListener(document, 'keyup', this.keyHandler);

    this.destroyShapes();
    this.removeHint();
};